No one wants or expects to get duped by a car dealership. Unfortunately, it happens more often than it should. If you're in the market for a new vehicle, protect yourself by recognizing the most common car dealer tricks and traps.

Scams happen on the car lot everyday. These aren't the clever and amusing schemes you'll see in movies like Catch Me If You Can or Matchstick Men. Car lot scams are nothing more than simple, petty tactics used by unethical dealers to trick you into spending more than you have to.

We're only thinking of you

Dealers love to say that they're looking out for your best interest; but they aren't always sincere. Here are some things to watch for:

VIN etching. Your dealer might recommend having the car's windshield etched to deter theft. Not a bad idea, but politely decline if he wants to charge you a premium for the service. You can buy a VIN etching kit online for $20 to $30.

Loan guaranty. Ignore any claim that your dealer makes about paying off your loan if you find yourself unable to meet that obligation. If you default and the dealer pays it off, you'll end up owing money and fees to the dealer instead of to the bank. Either way, your credit rating will be shot.

Affordable payments. Some dealers will want to negotiate with you on the car loan payment, rather than on the price of the car. They might say that they're trying to make it more affordable for you. But it's more likely that they're trying to confuse you into paying too much.

More fees, please?

What's another $1,500 when you've already agreed to pay $25,000? Some dealers like to strong-arm you into paying more by adding in fees after you've already agreed on a price. Here's how they do it:

Dealer prep. Every dealer will try to charge you dealer prep costs. Your job is to know ahead of time what the standard costs are for that car by checking an Internet site, like Edmunds.com. Try to negotiate these as low as possible. And never pay more than another dealer would charge, or more than what's listed on the sticker.

Extended warranty. It's your decision to purchase or not purchase an extended warranty. Period.

Bait and switch APR. You buy the car and take it home. A week later, you're notified that, due to a problem with your loan approval, your interest rate and monthly payment are being increased. The bait-and-switch APR scam is one of the most frustrating tricks a dealer can pull. Avoid this by arranging for financing before you walk into the dealership. Check with your bank, credit union, and online lending sites for more information.

In this storyline, it isn't the con artist who's the clever one-it's you. Keep an eye out for the warning signs and head for the door if you suspect someone's trying to rip you off.